@Article{ 2419,
title = {Insect-inspired estimation of egomotion},
journal = {Neural Computation},
year = {2004},
month = {11},
volume = {16},
number = {11},
pages = {2245-2260},
abstract = {Tangential neurons in the fly brain are sensitive to the typical optic flow patterns generated during egomotion. In this study, we examine whether a simplified linear model based on the organization principles in tangential neurons can be used to estimate egomotion from the optic flow. We present a theory for the construction of an estimator consisting of a linear combination of optic flow vectors that incorporates prior knowledge about the distance distribution of the environment and about the noise and egomotion statistics of the sensor. The estimator is tested on a gantry carrying an omnidirectional vision sensor. The experiments show that the proposed approach leads to accurate and robust estimates of rotation rates, whereas translation estimates are of reasonable quality, albeit less reliable.},
file_url = {/fileadmin/user_upload/files/publications/pdf2419.pdf},
web_url = {http://www.mitpressjournals.org/doi/pdf/10.1162/0899766041941899},
state = {published},
DOI = {10.1162/0899766041941899},
author = {Franz MO{mof}{Department Empirical Inference}; Chahl JS; Krapp HG{hkrapp}}
}
@Article{ 43,
title = {Binocular Contributions to Optic Flow Processing in the Fly Visual System},
journal = {Journal of Neurophysiology},
year = {2001},
month = {2},
volume = {85},
number = {2},
pages = {724-734},
abstract = {Integrating binocular motion information tunes wide-field direction-selective neurons in the fly optic lobe to respond preferentially to specific optic flow fields. This is shown by measuring the local preferred directions (LPDs) and local motion sensitivities (LMSs) at many positions within the receptive fields of three types of anatomically identifiable lobula plate tangential neurons: the three horizontal system (HS) neurons, the two centrifugal horizontal (CH) neurons, and three heterolateral connecting elements. The latter impart to two of the HS and to both CH neurons a sensitivity to motion from the contralateral visual field. Thus in two HS neurons and both CH neurons, the response field comprises part of the ipsi- and contralateral visual hemispheres. The distributions of LPDs within the binocular response fields of each neuron show marked similarities to the optic flow fields created by particular types of self-movements of the fly. Based on the characteristic distributions of local preferred directions and motion sensitivities within the response fields, the functional role of the respective neurons in the context of behaviorally relevant processing of visual wide-field motion is discussed.},
web_url = {http://jn.physiology.org/content/85/2/724.long},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}; Egelhaaf M}
}
@Article{ 81,
title = {Wide-field, motion-sensitive neurons and matched filters for optic flow fields},
journal = {Biological Cybernetics},
year = {2000},
month = {8},
volume = {83},
number = {3},
pages = {185-197},
abstract = {The receptive field organization of a class of visual interneurons in the fly brain (vertical system, or VS neurons) shows a striking similarity to certain self-motion-induced optic flow fields. The present study compares the measured motion sensitivities of the VS neurons (Krapp et al. 1998) to a matched filter model for optic flow fields generated by rotation or translation. The model minimizes the variance of the filter output caused by noise and distance variability between different scenes. To that end, prior knowledge about distance and self-motion statistics is incorporated in the form of a “world model”. We show that a special case of the matched filter model is able to predict the local motion sensitivities observed in some VS neurons. This suggests that their receptive field organization enables the VS neurons to maintain a consistent output when the same type of self-motion occurs in different situations.},
file_url = {/fileadmin/user_upload/files/publications/pdf81.pdf},
web_url = {http://www.springerlink.com/content/872k8k3yb0teaj9k/fulltext.pdf},
state = {published},
DOI = {10.1007/s004220000163},
author = {Franz MO{mof}; Krapp HG{hkrapp}}
}
@Article{ 241,
title = {Dendritic structure and receptive-field organization of optic flow processing interneurons in the fly.},
journal = {Journal of Neurophysiology},
year = {1998},
month = {4},
volume = {79},
number = {4},
pages = {1902-1917},
abstract = {Dendritic structure and receptive-field organization of optic flow processing interneurons in the fly. J. Neurophysiol. 79: 1902–1917, 1998. The third visual neuropil (lobula plate) of the blowfly Calliphora erythrocephala is a center for processing motion information. It contains, among others, 10 individually identifiable “vertical system” (VS) neurons responding to visual wide-field motions of arbitrary patterns. We demonstrate that each VS neuron is tuned to sense a particular aspect of optic flow that is generated during self-motion. Thus the VS neurons in the fly supply visual information for the control of head orientation, body posture, and flight steering. To reveal the functional organization of the receptive fields of the 10 VS neurons, we determined with a new method the distributions of local motion sensitivities and local preferred directions at 52 positions in the fly's visual field. Each neuron was identified by intracellular staining with Lucifer yellow and three-dimensional reconstructions from 10-μm serial sections. Thereby the receptive-field organization of each recorded neuron could be correlated with the location and extent of its dendritic arborization in the retinotopically organized neuropil of the lobula plate. The response fields of the VS neurons, i.e., the distributions of local preferred directions and local motion sensitivities, are not uniform but resemble rotatory optic flow fields that would be induced by the fly during rotations around various horizontal axes. Theoretical considerations and quantitative analyses of the data, which will be presented in a subsequent paper, show that VS neurons are highly specialized neural filters for optic flow processing and thus for the visual sensation of self-motions in the fly.},
web_url = {http://jn.physiology.org/content/79/4/1902},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg B{bhbg}; Hengstenberg R{hbg}}
}
@Article{ 367,
title = {A fast stimulus procedure to determine local receptive field properties of motion-sensitive visual interneurons.},
journal = {Vision Research},
year = {1997},
month = {2},
volume = {37},
number = {2},
pages = {225-234},
abstract = {We present a method to determine, within a few seconds, the local preferred direction (LPD) and local motion sensitivity (LMS) in small patches of the receptive fields of wide-field motion-sensitive neurons. This allows us to map, even during intracellular recordings, the distribution of LPD and LMS over the huge receptive fields of neurons sensing self-motions of the animal. Comparisons of the response field of a given neuron with the optic flow fields caused by different movements in space, allows us to specify the particular motion of the animal sensed by that neuron.},
web_url = {http://www.sciencedirect.com/science/article/pii/S0042698996001149},
state = {published},
DOI = {10.1016/S0042-6989(96)00114-9},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}}
}
@Article{ 525,
title = {Estimation of self-motion by optic flow processing in single visual interneurons.},
journal = {Nature},
year = {1996},
month = {12},
volume = {384},
number = {6608},
pages = {463-466},
abstract = {Humans, animals and some mobile robots use visual motion cues for object detection and navigation in structured surroundings1–4. Motion is commonly sensed by large arrays of small field movement detectors, each preferring motion in a particular direction5,6. Self-motion generates distinct 'optic flow fields' in the eyes that depend on the type and direction of the momentary locomotion (rotation, translation) 7. To investigate how the optic flow is processed at the neuronal level, we recorded intracellularly from identified interneurons in the third visual neuropile of the blowfly8. The distribution of local motion tuning over their huge receptive fields was mapped in detail. The global structure of the resulting 'motion response fields' is remarkably similar to optic flow fields. Thus, the organization of the receptive fields of the so-called VS neurons9,10 strongly suggests that each of these neurons specifically extracts the rotatory component of the optic flow around a particular horizontal axis. Other neurons are probably adapted to extract translatory flow components. This study shows how complex visual discrimination can be achieved by task-oriented preprocessing in single neurons.},
web_url = {http://www.nature.com/nature/journal/v384/n6608/pdf/384463a0.pdf},
state = {published},
DOI = {10.1038/384463a0},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}}
}
@Inbook{ 1235,
title = {Extracting egomotion from optic flow: limits of accuracy and neural matched filters},
year = {2001},
volume = {3},
pages = {143-168},
abstract = {In this chapter we review two pieces of work aimed at understanding the principal limits of extracting egomotion parameters from optic flow fields (Dahmen et al. 1997) and the functional significance of the receptive field organization of motion sensitive neurones in the fly’s visual system (Franz and Krapp 1999). In the first study, we simulated noisy image flow as it is experienced by an observer moving through an environment of randomly distributed objects for different magnitudes and directions of simultaneous rotation R and translation T. Estimates R’ of the magnitude and direction of R and t’ of the direction of T were derived from samples of this perturbed image flow and were compared with the original vectors using an iterative procedure proposed by Koenderink and van Doom (1987). The sampling was restricted to one or two cone-shaped subregions of the visual field, which had variable angular size and viewing directions oriented either parallel or orthogonal with respect to the egomotion vectors R and T. We also investigated the influence of environmental structure, such as various depth distributions of objects and the role of planar or spherical surfaces. From our results we derive two general rules how to optimize egomotion estimates: (i) Errors are minimized by expanding the field of view. (ii) Sampling image motion from opposite directions improves the accuracy, particularly for small fields of view.},
web_url = {http://link.springer.com/content/pdf/10.1007%2F978-3-642-56550-2_8.pdf},
editor = {Zanker, J.M. , J. Zeil},
publisher = {Springer},
address = {Berlin, Germany},
booktitle = {Motion Vision: Computational, Neural, and Ecological Constraints},
state = {published},
ISBN = {978-3-642-62979-2},
DOI = {10.1007/978-3-642-56550-2_8},
author = {Dahmen H-J; Franz MO{mof}; Krapp HG{hkrapp}}
}
@Inbook{ 342,
title = {Visual sensation of self-motion in the blowfly Calliphora.},
year = {1998},
volume = {2},
pages = {53-70},
file_url = {/fileadmin/user_upload/files/publications/pdf342.pdf},
editor = {C.Taddei-Ferretti},
publisher = {World Scientific Publishers},
address = {5 Tuh Tuck Link, 596224 Singapore},
state = {published},
author = {Hengstenberg R{hbg}; Krapp HG{hkrapp}; Hengstenberg B{bhbg}}
}
@Techreport{ 1529,
title = {Wide-Field, Motion-Sensitive Neurons and Optimal Matched Filters for Optic Flow},
year = {1998},
month = {6},
number = {61},
abstract = {We present a theory for the construction of an optimal matched filter for
self-motion induced optic flow fields. The matched filter extracts local flow
components along a set of pre-defined directions and weights them according to
an optimization principle which minimizes the difference between estimated and
real egomotion parameters. In contrast to previous approaches, prior knowledge
about distance and translation statistics is incorporated in the form of a
"world model". Simulations indicate that the matched filter model yields
reliable self-motion estimates. A comparison of the weight distribution used
in the model with the local motion sensitivities of individual and small
groups of interneurons in the fly visual system shows a close
correspondence. This suggests that these so-called tangential neurons are
tuned to optic flow fields induced by rotation or translation along a
particular axis. They seem to weight the local optic flow according to the
contribution of input noise and the expected variability of the translatory
flow component. Their local preferred directions and motion sensitivities can
be interpreted as an adaptation to the processing requirements of estimating
self-motion from the optic flow.},
note = {This technical report has also been published elsewhere},
state = {published},
author = {Franz MO{mof}; Krapp HG{hkrapp}}
}
@Poster{ 276,
title = {VS-neurons as matched filters for self-motion-induced optic flow fields},
year = {1998},
month = {5},
volume = {26},
pages = {419},
file_url = {/fileadmin/user_upload/files/publications/pdf276.pdf},
file_url2 = {/fileadmin/user_upload/files/publications/ps276.ps},
event_name = {26th Göttingen Neurobiology Conference: New Neuroethology on the Move},
event_place = {Göttingen, Germany},
state = {published},
author = {Franz MO{mof}; Hengstenberg R{hbg}; Krapp HG{hkrapp}}
}
@Poster{ 574,
title = {Distribution of roll motion sensitivity in the eyes of Calliphora: a comparison between neurons and behaviour.},
journal = {Brain and Evolution, Vol. II, (Eds.) N. Elsner, H.U. Schnitzler. Thieme, Stuttgart 1996},
year = {1996},
pages = {349},
file_url = {/fileadmin/user_upload/files/publications/pdf574.pdf},
state = {published},
author = {Hengstenberg R{hbg}; Krapp HG{hkrapp}}
}
@Poster{ 1303,
title = {Filter neurons for specific optic flow patterns in the fly's visual systems},
year = {1995},
month = {9},
volume = {4},
pages = {255},
abstract = {The control of locomotion in a given environment requires information about instantaneous self-motion. Visually oriented animals, including man, may gain such information by analyzing the momentary optic flow pattern generated over both eyes during relative movement between animal and environment. Optic flow patterns can be described by vector fields where each single vector indicates the direction and velocity of the local relative movement at a certain position within the visual field. An optic flow pattern depends upon a set of motion parameters, namely (i) the direction of gaze and (ii) the rotatory and (iii) translatory components of self-motion. The translatory flow vectors also depend an the distance between visual objects and the eyes. Therefore, optic flow fields contain valuable information about the 3D-layout of the surroundings and instantaneous self-motion (Koenderink and van Doorn, 1987).
About 50 motion-sensitive, wide-field interneurons which are assumed to be' involved in locomotor control are located in the third visual neuropil (lobula plate) of the blowfly's (Calliphora erythrocephala) visual system (Hausen, 1993). The output of many direction-specific movement detectors (EMDS) with small receptive fields are spatially integrated in a retinotopic manner an the dendrites of these interneurons.
Are such interneurons adapted to sense specific aspects of the momentary optic flow field? To address this question, we investigated the receptive field organization of 10 identifiable interneurons of the so called vertical-system (VS; Hengstenberg, 1982) in great detail. We recorded intracellularly from the VS-neurons to determine the spatial distribution of local preferred directions and motion sensitivities at 52 positions spaced equally over the ipsilateral visual hemisphere (for method see: Menzel and Hengstenberg, 1991; Krapp and Hengstenberg 1992). The resulting response fields of the VS-neurons (about 90 recordings) show striking similarities to optic flow fields generated by specific motions in space (Krapp and Hengstenberg, 1994).
By applying an iterative least square formalism (Koenderink and van Doorn, 1987) to the response fields we calculated the optimal self-motion parameters (translatory and rotatory component) for each VS-neuron. These parameters describe an optic flow field that best fits the respective measured response field. To find out whether the VS-neurons are functionally tuned more to the translatory or to the rotatory component of self-motion we systematically varied the optimal motion parameters. The error between the measured response field and the calculated optic flow field increases if both the translatory and the rotatory component deviate from the optimal motion parameters. The increase in the error is almost the same if only the rotatory component is varied. In contrast, if the translatory component is varied and the rotatory component is kept optimal the increase in the error is considerably smaller.
The analysis of the response fields of the VS-neurons leads to the following conclusion: the VS-neurons are functionally tuned to sense rotations around different horizontally aligned body axes. The neurons VS1-VS3 are optimized to sense optic flow fields generated during nose-up pitch. VS4-VS7 are filter neurons for counterclockwise roll and VS8-VS10 are adapted to rotations around an axis that lies between the pitch and roll axes. Thus, the signals of the VS-neurons could contribute directly to visual flight control and gaze stabilization.},
file_url = {/fileadmin/user_upload/files/publications/pdf1303.pdf},
event_name = {4th International Congress of Neuroethology},
event_place = {Cambridge, UK},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}}
}
@Poster{ 1301,
title = {Comparison between optic fields and response fields of visual interneurons in the lobula plate of the blowfly Calliphora.(In:Learning and Memory,
ed.by Elsner,N. and Menzel, R.)},
year = {1995},
pages = {404},
file_url = {/fileadmin/user_upload/files/publications/pdf1301.pdf},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}}
}
@Poster{ 515,
title = {Correspondence of dendritic field structure, receptive field organization and specific optic flow patterns in visual interneurons of the blowfly Calliphora.(In:Sensory Transduction, Vol 2, ed. by Elsner,N.,Breer,H.)},
year = {1994},
pages = {453},
file_url = {/fileadmin/user_upload/files/publications/pdf515.pdf},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg B{bhbg}; Hengstenberg R{hbg}}
}
@Poster{ 1297,
title = {Representation of specific optical flow fields in lobula plate neurons of the blowfly Calliphora.(In:Gene, Brain, Behavior, ed. by Elsner,N.and Heisenberg,M.)},
year = {1993},
pages = {357},
file_url = {/fileadmin/user_upload/files/publications/pdf1297.pdf},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}}
}
@Poster{ 1294,
title = {Reliability of a fast method to determine locally the preferred direction of motion sensitive neurons},
year = {1992},
month = {6},
pages = {306},
file_url = {/fileadmin/user_upload/files/publications/pdf1294.pdf},
event_name = {Rhythmogenesis in Neurons and Networks: 20th Göttingen Neurobiology Conference},
event_place = {Göttingen, Germany},
state = {published},
author = {Krapp HG{hkrapp}; Hengstenberg R{hbg}}
}